Focus

Tambora bicentenary

In April 1815, the eruption of Tambora Volcano in Indonesia — one of the largest in recorded history — blasted ash and gases into the atmosphere purportedly causing widespread cooling and crop failure. 200 years on, the dynamics and effects of the Tambora eruption continue to fascinate and inform understanding of other giant eruptions in the past and future. In this Web Focus, we bring together a collection of opinion pieces that discuss current understanding of the Tambora event and other giant eruptions, and their impacts on society and the environment.

The year without a summer - pp246-248

J. Luterbacher & C. Pfister

doi:10.1038/ngeo2404

The 1815 eruption of Tambora caused an unusually cold summer in much of Europe in 1816. The extreme weather led to poor harvests and malnutrition, but also demonstrated the capability of humans to adapt and help others in worse conditions.

Tying down eruption risk - pp248-250

Stephen Self & Ralf Gertisser

doi:10.1038/ngeo2403

200 years after the eruption of Mount Tambora, the eruption volume remains poorly known, as is true for other volcanic eruptions over past millennia. We need better records of size and occurrence if we are to predict future large eruptions more accurately.

From the archives

News and Views

Volcanology: Volcanic bipolar disorder explained -

Mark Jellinek

doi:10.1038/ngeo2067

Eruptions come in a range of magnitudes. Numerical simulations and laboratory experiments show that rare, giant super-eruptions and smaller, more frequent events reflect a transition in the essential driving forces for volcanism.

Volcanism: Eruptions and extinctions -

Nicholas Christie-Blick

doi:10.1038/ngeo598

Fossils from southern China provide evidence for a mass extinction during middle Permian time, 260 million years ago. The close association of this event with an outpouring of lava, initially into the sea, indicates that explosive volcanism may have been the cause.

The position of the intertropical convergence zone may be influenced by aerosols. A 450-year-long precipitation record from Belize confirms a southward shift associated with increasing anthropogenic aerosol emissions in the Northern Hemisphere.

Giant volcanic eruptions occur when large volumes of magma accumulate in crustal reservoirs and do not cool and crystallize to form a solid pluton of rock within the crust. Geochronological dating of a pluton from Elba, Italy, shows that the magma solidified in the crust within just 10–40 thousand years of being injected into the crust, implying that the time window for an eruption was short.

Global mean surface and tropospheric temperatures have shown slower warming since 1998 than found in climate model simulations. A detailed analysis of observations and climate model simulations suggests that the observed influence of volcanic eruptions on tropospheric temperature has been significant, and that the discrepancy between climate simulations and observations is reduced by up to 15% when twenty-first century volcanic eruptions are accounted for in the models.

Small influence of solar variability on climate over the past millennium -

Andrew P. Schurer, Simon F. B. Tett & Gabriele C. Hegerl

doi:10.1038/ngeo2040

Climate variations over the past 1,000 years correspond to solar fluctuations, but the magnitude of the solar variability is unclear. An analysis of numerical simulations and climate reconstructions suggests that the amplitude of solar forcing was small over this interval, with the main climate forcing derived from volcanic eruptions and greenhouse gas concentrations.

Two pulses of extinction during the Permian–Triassic crisis -

Haijun Song, Paul B. Wignall, Jinnan Tong & Hongfu Yin

doi:10.1038/ngeo1649

Over 90% of marine species were lost during the end-Permian extinction. Fossil data show that the crisis in China was marked by two distinct phases of marine extinction separated by a 180,000-year recovery period.

Caldera size modulated by the yield stress within a crystal-rich magma reservoir -

Leif Karlstrom, Maxwell L. Rudolph & Michael Manga

doi:10.1038/ngeo1453

The size of the caldera formed when the surface collapses after a large volcanic eruption is thought to reflect the size of the evacuated magma chamber. Numerical modelling shows that magma stored in different parts of the chamber can be mobile or locked, so caldera size may only correspond to the volume of evacuated mobile magma.

Influence of human and natural forcing on European seasonal temperatures -

The impact of external influences on European temperatures before 1900 has been thought to be negligible. An analysis of reconstructions of seasonal European land temperatures and simulations from three global climate models instead suggests that external forcing is responsible for a best guess of 75% of the observed winter warming since the late seventeenth century.

The impact of volcanic forcing on tropical temperatures during the past four centuries -

Rosanne D'Arrigo, Rob Wilson & Alexander Tudhope

doi:10.1038/ngeo393

The effect of volcanism on low-latitude climate has been difficult to quantify. A compilation of tropical and subtropical annually resolved climate reconstructions shows a correlation between low sea surface temperatures and low-latitude volcanic activity over the past four centuries.

Reconciliation of halogen-induced ozone loss with the total-column ozone record -

The observed depletion of the stratospheric ozone layer from the 1980s onwards is attributed to halogens released through human activities. Model simulations show that stratospheric ozone loss has declined by over 10% since stratospheric halogen loading peaked in the late 1990s, indicating that the recovery of the ozone layer is well under way.